Variable pitch fan blade assembly



March 16, 1948.

. S. C. EARLEY EI'AL VARIABLE PITCH FAN BLADE ASSEMBLY Filed, Nov. 20,1944 2 Sheets-Sheet 2 IHI ' ELMORE J. SHNDER3 ayahalu 41am;

Patented Mar. 16, 1948 UNITED STATES PATENT F 2,437,810 F ICE 2,437,810VARIABLE rrron FAN BLADE ASSEMBLY Samuel C. Eariey, Norman B. Earley,Elmore J. Sanders, Willard C. Skareen, Ray L. Davies, and Joseph A.Hughes, Toledo, Ohio, assignors, by mesne assignments, to Evans ProductsCompany, Detroit, Mich., a corporation of Delaware Application November20, 1944, Serial No..564,278

4 Claims. (01. 170-163) 1 1 This invention relates to variable pitchfans of the type used in connection with the cooling system of aninternal combustion engine employed either on vehicles or in stationaryinstallations for the purpose of varying the fan blade pitch inaccordance with the requirements of service.

An object is to produce a variable pitch fan blade assembly of the abovecharacter having the new and improved features of construction,arrangement and operation hereinafter described, to the end that thestructure can be readily and conveniently assembled and disassembled,can be manufactured emciently and economically, and can be maintainedemciently in operation.

For purposes of illustration but not of limitation an embodiment of theinvention is shown in the accompanying drawings, in which Figure l is afragmentary side elevation, partly diagrammatic of the variable pitchfan assembly installed on an internal combustion engine in connectionwith engine cooling system;

Figure 2 is an enlarged vertical sectional elevation of the variablepitch fan blade assembly, showing in elevation an operating thermostat;and

Figure 3 is a front end elevation of the fan blade assembly, parts beingbroken away to show the operating mechanism and certain of the fanblades being omitted.

The illustrated embodiment of the invention comprises an internalcombustion engine E, which is provided with the usual cooling liquidjacket J and a liquid circulating pump P. The pump P draws liquid fromthe lower end of the radiator core B through a tube (not shown) to theJacket from which it returns to the radiator tank T through a tube S.Manifestly, the above structure is conventional.

Leading from the pump P is a tube in, which extends to a thermostathousing ii, and a tube 52 extends from the housing to a portion of thecooling jacket in the region of the tube S. Thus it will be apparentthat a portion of the cooling liquid is bypassed through the thermostathousing ii so that the latter is supplied with liquid substantially ofthe temperature of that drawn from the radiator core R. The thermostathousing ii is fixed to the front end of the engine and mounted forrotational movement directly in front of the housing ii is a variablepitch fan blade assembly, generally indicated at A. The assembly Aincludes a hub it, on which belt sheaves i i are integrally formed, thehub being suitably mounted for rotation, although the detail structureof the mounting is not shown since it forms no part of the presentinvention. Reference is hereby made to the patent to Dewey 2,225,209

2 dated December 7, 1940, wherein one form of mounting is shown anddescribed.

At the forward end of the hub i3 is an attaching flange l5, to which afan blade unit B is rigidly secured by a series of bolts lSa. Forming apart of the unit B is a plurality of fan blades I6, which, as willhereinafter appear, are mounted for turning movements in response tochanges in the temperature of cooling liquid.

Suitably mounted within the housing It in thermal contact with thecooling liquid therein is a thermostat I 1 into which an actuating rodor shaft I8 is slidable. The structure of the thermostat forms no partof the present invention so that detail description and illustrationthereof is not considered necessary. Suffice it to say that as thetemperature of the cooling liquid increases above a predetermineddegree, the shaft I8 is forced inwardly or to the left of Figure 2 andis returned or moved to the right by a coil spring l9 as the temperatureof the liquid drops. Thus the fan blades operate to draw or blow airthrough the radiator R in accordanc with temperature conditionsprevailing in the cooling liquid, as will be readily understood by thoseskilled in the art. Various forms of thermostats may be employed for thepurpose, for example, the well known bellows or Sylphontype thermostatmay be used to advantage.

The outer end of the shaft i8 is screw threaded to receive a flangedsleeve 20 and having a press fit thereon is an antifriction thrustbearing 2|. A nut 22 on the end of the shaft is secures the sleeve 20 inplace. The outer race of the bearing unit 2| is pressed into anactuating sleeve 23, the inner side of which is cupped to provide alubricant reservoir and the outer side of which is cupped to provide aseat for the coneshaped helical spring IS. The smaller end of the springi9 bears against a cover plate 24, which is held in place by the boltsIlia and screws 25 against an outer hub section 26.

The outer hub or housing section 26 and the inner hub or housing section21 are similarly formed and each comprises an annulus having matingsocketed portions 28 for the fan blade mountings, the same beingarranged in equidistantly spaced relation. The number of blades may varybut in the form illustrated, provision is made for six blades.Intermediate the socketed portions are web portions 29, through whichthe bolts iiia pass. Peripheral flange portions 30 on each hub sectionreceive bolts 3 I, thereby securely to fasten the sections together. Itwill be apparent that the actuating sleeve 23 fits freely within thecentral opening provided by the hub sections 26 and 21 so that it canreciprocate axially therein in response to the thermally actuated shaftl8 and the coil spring l9. Such reciprocal movement imparts rotary orturning movements simultaneously to the several fan blades I3. In thisinstance the actuating sleeve is formed with a plurality of rectangulargrooves 32, one being provided for each fan blade and the same beingdisposed in planes at right angles to the axis and the direction ofmovement of the sleeve 23 and being open at the outer or peripheralside. Mounted within each groove 32 is an elongate block or shoe 33,which has a snug fit therein and has its outer surface approximatelyfiush with the adjacent peripheral surface of the sleeve 23. It shouldbe observed that the outer surface of the sleeve 23 is provided with aseries of flat surfaces, one for each fan blade, and arranged inparallel relation to the bottom walls of the grooves 32, respectively.

The socketed portions 28 in the hub sections 26 and 21 each includes aninner cylindrical socket 28a and an outer cylindrical socket 28b, whichis of considerably greater diameter. Mounted within the socket 28a forrotary movements is an annular block or disc 34, which has a press fitconcentrically on a reduced pin-like end portion 35 of the fan bladeshaft. A set screw 33 in the disc 34 engages the shaft portion 35 toassist in preventing relative rotation. Having a press fit in the disc34 at one side or eccentrically thereof is a pin 31, which dependsbeyond the lower side thereof and extends relatively loosely into anopening in the subjacent actuating shoe 33 so that horizontal movementof the shoe 33 along with the sleeve 23 imparts rotary motion to the fanblade shaft.

Arranged directly above the shaft portion 35 i a screw threaded shaftportion 38, in which a jack nut 33 is mounted. The nut 39 may be turnedto force the disc 34 from the shaft in the event of damage or breakageof the pin 31, it being understood that the set screw 36 is firstloosened.

Abutting against the upper side of the nut 39 is an antifriction bearingunit 40, which is mounted on a cylindrical shaft portion 4| of slightlygreater diameter than the screw threaded shaft portion 38. It will beevident that the nut 39 not only serves to retain the bearing unit 40 inplace but also to provide a jack screw as above explained. The outerrace .of the bearing unit 49 fits within a sleeve 42, which has anoutwardly extending flange 43 at the lower end fitting in an annulargroove 44 in the hub sections. The sleeve 42 is mounted within the outercylindrical socket 28b. At the upper end of the sleeve 42 is an inwardlyextending flange 45, which fits over the upper end of the bearing unit40 in abutting relation to an annular collar 46 of the fan blade shaft.The collar 46 is integral with a fan blade supporting bracket 41 towhich the fan blade l6 is secured by rivets 48 substantially as shown.

In operation it will be understood that movement of the shaft I8 inresponse to temperature variations is transmitted to the sleeve 23 whichthrough the shoe 33 and eccentric pin 31 rocks the blade I6 in onedirection or the other depending upon the direction of longitudinalmovement of the shaft. Thus feathering of the blade is accomplished inaccordance with the temperature of the cooling liquid circulatingthrough the jacket enclosing the engine cylinders. of course, it will bemanifest that although a single fan blade has been described, identicalmounting is provided for each of the other blades, so that the pitch ofall blades are conjointly varied.

Adequate lubrication is afforded to the assembly, because, as abovepointed out a lubricant chamber is provided between the hub sections 26and 21, so that all moving parts are kept lubri- 4 cated at all times.In the event that the lubricant builds up pressure or trapped air withinthe chamber creates undesirable pressure, the same is automaticallyrelieved by a spring tensioned relief valve 49 in the cover plate 24,which closes as soon' as the pressure is relieved.

Numerous changes in details of construction, arrangement, operation andchoice of materials may be effected without departing from the spirit ofthe invention especially as defined in the appended claims.

What we claim is:

1. A variable pitch fan assembly comprising a pair of abutting hubsections having a central apertured portion, a plurality of fan bladesmounted for rotary movement in said hub sections and including fan bladesupporting stub shafts extending radially between said sections. bearingmeans for the respective stub shafts mounted between and supported bysaid hub sections, a disc fixed to the end portion of each of said stubshafts, a pin disposed parallel to and eccentric with said stub shaft,carried by the respective disc and projecting inwardly therefrom, asleeve disposed in said apertured hub portion for axial movement,grooves in the peripheral portion of said sleeve arranged at rightangles to the axis thereof and extending at right angles to said stubshafts, one groove being provided for each pin, a block fitting in eachgroove having a bearing socket for the adjacent pin, and means foraxially .moving said sleeve.

2. A variable pitch fan assembly comprising a pair of abutting hubsections having a central aperture and a plurality of spaced radiallydisposed shaft receiving sockets, a plurality of fan blades mounted forrotary movement in said hub sections and each having a stub shaftextending into one of said sockets, an antifriction bearing for eachshaft mounted in the outer portion of the respectivesocket, a discpressed on to the inner portion of each shaft, an eccentric pin carriedby each disc and projecting inwardly therefrom, a screw threaded portionon each shaft intermediate each disc and antifriction bearing, a nut oneach screw threaded portion adapted to serve as a jack to remove saiddisc, an actuating sleeve in said hub aperture having a plurality offlat peripheral portions, a plurality of grooves rectangular incross-section formed in the peripheral portions of said sleeve arrangedat right angles to the axis thereof and extending at right angles tosaid stub shaft, one groove being provided for each pin, a rectangularblock snugly fitting in each groove having a bearing for the adjacentpin, and means for imparting axial movement to said sleeve.

3. A variable pitch fan assembly as claimed in claim 2, which comprisessleeves disposed within said sockets respectively and providingmountings for said antifriction bearings, said hub sections havinginternal grooves, and outwardly extending flanges on said sleevesengaging in said grooves respectively.

4. A variable pitch fan assembly comprising a pair of abutting hubsections having a central apertured portion. a plurality of fan blades,means for mounting said fan blades for rotary movement in said hubsections, said means including fan blade supporting stub shaftsextending radially between said sections, bearing means for therespective stub shafts mounted between and supported by said hubsections, a pin carried by and mounted eccentrically of the innerportion of each stub shaft. a concave-convex sleeve viding a seat forthe other end of said spring, the

concave face of the sleeve providing a lubricant reservoir, and meansfor imparting axial movement to said sleeve.

SAMUEL C. EARLEY. NORMAN B. EARLEY. ELMORE J. SANDERS. WILLARD C.SKAREEN. RAY L. DAVIES. JOSE'PH A. HUGHES.

REFERENCES CITED The following references are of record in the 5 file ofthis patent:

UNITED STATES PATENTS Number Number Name Date Johansson Jan. 27, 1903Brown Jan. 16, 1906 Kuleck Oct. 8, 1929 Squires July 16, 1935 Dewey Dec.17, 1940 Roby 'Apr. 28, 1942 FOREIGN PATENTS Country Date France June16, 1933 (Addition to 722,641)

